Electric fuse and method of preparing same



April, 6 1926.

T. F.COTE

ELECTRIC FUSE AND METHOD or PREPARING 5mm original Filqd Oct. 13,

gmwntoz Fa? fa Patented Apr. 6, 1926.

UNITED STATES THOMAS F. COTE, OF CHICAGO, ILLINOIS.

ELECTRIC FUSE AND IVIETHOID 0F PREPARING SAME.

Application filed October 13, 1921, Serial No. 507,436.

To all whom it may concern Be it known that I, THOMAS F. Corr, a subject of the King of Great Britain, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in an Electric Fuse and Method of Preparing Same; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use, the same.

This invention relates to an electric fuse and method of preparing the same.

The invention particularly aims to provide a fuse and method of preparing the same having the surface tension thereof increased above the normal degree, so that upon short circuiting the degree of arcing will be materially reduced; to provide a fuse in which said factor ofsurface tension can be raised to a value at which it will open the circuit at the instant or simultaneously with the fuse reaching a molten state so that little, if any metallic vapor, will be produced, and to provide a fuse having a portion stretched to change the distribution of the inter-molecular forces as by hammering, knurling, or embossing, to increase said surface tension.

Additional objects and advantages will appear and become apparent as the description is hereinafter considered with relation to accompanying drawings illustrating one practical embodiment thereof.

Referring specifically to the drawing, Figure 1 illustrates a fuse in plan constructed in accordance with my invention;

Figure 2 is a side elevation thereof; Figure 3 is a plan view of another fuse constructed in accordance with my invention, and

Figure 4 is a longitudinal cross sectional view taken on the line 4-4 of Figure 3.

Throughout the drawings like reference characters designate like or similar parts.

The forms of fuses illustrated are elongated strips of metal fusible by application of heat thereto. It is obvious that the shape may be varied and they may be secured in plugs or in any suitable manner, as according to present practice, and therefore are to be taken asexamples and conventional only.

Renewed August 25, 1925.

mal width of the fuse while the portions 8 outside of said lines indicate the increase in width. Due to this flattening of portion 6, its surface tension is increased due to a change in distribution of the inter-molecular forces of the portion 6. The portion 6 is preferably reduced in thickness by hammer- 111g.

In the form shown in Figures 3 and at, a strip 9 is knurled and embossed on opposite sides, and with the embossed portions in staggered relation as at 10. This knurling and embossing, like the flattening of portion 6, changes the distribution of the intermolecular forces of the fuse thereof which increases the surface tension. The knurling or embossing of the fuse may be accomplished' by hand or machinery, or in any manner desired.

It is to be understood of course that the foregoing are merely examples of ways in which the surface tension of any portion of the fuse may be increased and that such illustrations are to be taken by way of example only, since I may resort to other means of effecting the result when desired or necessary.

Due to the increase of the surface tension, the distribution of the inter-molecular forces of the fuse is changed, so that the degree of vaporization of the fuse when the latter is short circuited is greatly reduced, thus diminishing the possibility of arcing. The circuit will be opened practically simultaneously with or at the instant the fuse reaches a molten state, and thus little or no metallic vapor will be formed and the possibility of arcing greatly diminished.

It may be mentioned that to increase the surface tension, it is essential that the strips 5 and 9 should be initially of the same width and thickness as the portions 6 and 10, so that the flattening and embossing will occur without any increase in the cross-sectional What I claim as my invention is area of the portionsof the fuses having An electric fuse having its central portion 10 their surface tension increased. knurled and embossed on opposite sides As merely practical embodiments by Way thereof and in relatively staggered relationof example have been illustrated and deship to increase the surface tension thereof.

scribed, it is to be understood that changes In testimony whereof I afiiX my signature.

in the details and in the method may be resorted to Within the spirit and scope. THOMAS F. COTE. 

